CX3CL1 and idiopathic pulmonary fibrosis: Interestingly, we found some cells co-expressing CX3CL1-CX3CR1 in control lungs as well as in hyperplastic epithelium and fibroblasts in IPF lungs, suggesting that an epithelium-fibroblast crosstalk mediated by the CX3CL1-CX3CR1 axis could be possible.